The .22-caliber bullet struck a vent underneath a row seats and a fragment hit the 47-year-old woman around 6:35 a.m., police and the agency said. The fragment did not penetrate her clothes but she was taken to a hospital for observation.

The woman told WGN-TV she was on her way to work when she was struck by the bullet. She said there were not a lot of people on the bus at the time.

The No. 47 bus was heading east on 47th Street when the incident occurred at Kildare, according to CTA spokeswoman Catherine Hosinski. Passengers were transferred to the next bus on the route.

Chicago Police work at the scene where a woman was grazed in the leg this morning when, according to CTA officials, an "unattended gun" fell from the seat of a CTA bus and hit the floor, causing it to go off.

On Wednesday night, TBS will air a special episode of "Conan" filmed entirely in Cuba, making it the first American late-night show to broadcast from the island nation since the embargo went into effect in 1962. Host Conan O'Brien will follow in the footsteps of Jack Paar,...